Mechanical pressure device



Jan 12 1926..

A. w. HELMHOLTZ T AL MECHANICAL PRESSURE DEVICE Filed Oct. 1'7 1924 Patented J an. 12, 1926.

UNITED STATES PATENT OFFICE.

MECHANICAL PRESSURE DEVICE.

Application filed .pctober 17, 1924. Serial No. 744,184.

To all whom it may concern.

Be it known that we, ARTHUR V. HELM- HOLTZ and DENT FERRELL, citizens of the United States, residing, respectively, "at Harrisburg, in the county of Saline and State of Illinois, and at Harrisburg, in the county of Saline-and State of Illinois, have jointly invented certain new and useful Improvements in Mechanical Pressure Devices, of which the following is a specification.

This invention relates to new and improved method and means for blasting and more particularly, to a method and means adapted to produce effective blasting pres sure by mechanical means without combustion. The blasting as now carried out in coal mines and the like, by means of usual types of explosives is a source of danger and of delay to the mine operations. It is customary to blast only once at the end of each shift-of working. This is necessary, since due to the dangers from the blast, the workmen must be withdrawn from the mine at the time of the blast and for a sufiicient time thereafter to permit the diifusion of any dangerous gases evolved by the combustion of the explosive.

It is an object of the present invention to provide means for building up a disruptive blasting pressure by mechanical means.

It is a further object to provide means and method of this character which can be carried out without the use of any materials giving off gases, which are dangerous to life or to the mine structure.

An additional object is to provide method of this character adapted to be carried out by comparatively simple apparatus, the expendible portions of which may be replaced at comparatively low' cost.

' Other and further objects will appear as the description proceeds.

We have shown in the accompanying drawings apparatus for carrying out our process.

In Figure 1, the apparatus is shown in place in a'drili hole.

j In Figure 2,, one form;pix-cartridge and,

an enconnection is shown in section on larged scale, and

Figure 3 shows a modified form of cartridge.

Referring first to Figure 1, the cylindrical cartridge 11 is located in a drill hole 12, formed in a body of coal, or other material 13'. The outer portion of the drill hole is tamped in the customary manner as shown at 14. The pipe 15 leads from the cartridge 11 to the control valve 16 and this valve is connected by pipe 19 to a pressure pump 20. The fluid used is supplied to pump 20 by pipe 17 leading from tank 18.

A form of cartridge shown in Figure 2 comprises the cylindrical casing 1, provided with a portion 2 havin the passage 3 therein connected to the pipe 4. This pipe 4 leads to the valve 5 and thence through pipe 6 to a pump such as shown in Figure 1 or to any other suitable source of fluid under pressure. The rings 7 are secured to the inner surface of the casing 1, adjacent the opposite ends by welding, brazing or by any su table method. The outer rings 8 are threaded into the ends of the casing 1 and retain in place the closure discs 9.

' The'form of construction shown in Figure 3 comprises the cylindrical casing 19 provided with one integral solid end 20. The pipe 21 is threaded into the end 20 and leads to a 'control valve and a source of pressure supply as shown in other figures. The opposite end of the casing 19 is cut away and internally threaded to receive the ring 22, which serves to retain in place the rupturable closure disc 23.

In the use of the apparatus shown any non-combustible gas, vapor or liquid can be used and we specifically mention as suitable, carbon dioxlde, nitrogen, ordinary atmospheric ainor' such combinations of these as may be suitable for the effect desired; Before being placed in the bore hole, the cartridge may or may not be filled with the material as desired.

It will usually however, be found preferable to have it filled with material at a pressure somewhat less than at which the pressure disc is adapted to be ruptured. For example, m acasewhere it is estimated that =5,0fi0xiipm-inds of pressure are required to I remove the material to be shot, the procedure would normally be to load the container or cartridge to a pressure of approximately 4,000 pounds before insertion in the drill hole. Then when the shot is to be fired, the valve is opened to permit the building up of the pressure to the 5,000 pounds, at which the disc will be ruptured and the blasting pressure liberated in the bore hole. Obviously to build up the pressure from 4,000

to 5,000 pounds, it will be necessary to pass through the pipe into the cartridge but a comparatively small quantity of the material used.

Certain other methods of blasting have been proposed where it is intended to tamp the drill hole =and force liquid under pressure directly under the drill hole. This has proven impractical since it has been necescary to introduce very large volumes under high pressure in order to build up pressure fast enough to offset leakage through natural or produced fissures in the coal seam. This has proven almost impossible and commercially impractical since the friction loss in the supply pipe alone has been suflicient to prevent the building up ofi effective pressure. In the present case, there is no loss through fissures, as the container is not ruptured until the desired pressure has been built up. Where the cartridge is inserted with the greater portion of the desired pressure already built up, the addition of a very small quantity of material is required, consequently friction losses in the supply pipe are reduced to a minimum.

The forms of containers shown are comparatively cheap and may be used repeatedly. The only elements that will be necessary to replace after each shot are the rupturable discs and the cost of these will be very low. The cost of the blasting material will be also low. Carbon dioxide, which we consider particularly adapted 'for this Work. can be cheaply secured and may be carried in the containers under pressure in liquid form, as its critical temperature is 86-7 Farhrenheit, which is materially above the temperature usually found in mines.

This form of blasting has important added advantages over usual types of explosives, in that the blasting forces can be controlled by using 'discs adapted to rupture at any desired pressure. In this Way a maximum percentage of lump coal can be secured. This is extremely important as the demand and price offered for lump coal has becomea serious factor affecting the life of many coal mines. A further feature lies in the fact that it will be possible to blast by this method without necessitating the miners leaving the mine. There will be no flame generated by the pressure released, nor will there be any gases afiecting life or respiraplace a small mine on a par with a large mine.

The particular forms of apparatus shown ma be modified to meet the varying conditlons and we contemplate such changes as come Within the spirit and scope of the appended claims.

We claim:

1. The method of blasting which com rises inserting into a drill hole a closed rigi container, connecting the container to a source of fluid supply and forcing fluid into the closed container, under pressure suflicient to rupture a wall of the container, the rupture of the container wall permitting a sudden blasting pressure in the drill hole.

2. The method of blasting which comprises inserting in a drill hole a closed container filled with a compressible fluid not a liquid under atmospherlc pressure and temperature, connecting the container to a source of additional fluid supply, and forcing additional fluid into the container under pressure whereby the pressure in the container is built up to an amount sufficient to rupture a wall of the container, the rupture of the container wall permitting a sudden blasting pressure in the drill hole.-

3. Blasting apparatus comprising a closed container adapted to fit in a drill hole, said container having rigid walls a portion of the wall of said container being of less strength than the remainder of the container wall, a pipe connected to said container and adapted to extend beyond the drill hole, means for supplying fluid under pressure to the pipe and means for controlling the flow of the fluid.

4. Blasting apparatus comprising a cylindrical closed container, adapted to fit in a drill hole, an end of said container being removable and replaceable and bein of less strength than the Walls of the cylmder, a. pipe connected to the container and adapted to extend beyond the drill hole, means forsupplying fluid under pressure to the pi and means for controlling the flow of t "e fluid through the pipe.

5. The method of blasting which comprises inserting into a drill hole a closed container, connecting the container to. a source of supply of liquid carbon dioxide and forcing liquid carbon dioxide into the closed container under suflicient pressure to rupture a Wall of the container, the ruptureof the container wall permitting the gasification of the carbon dioxide which causes a blasting pressure in the drill hole.

6. The method of blasting which comp ises inserting into a drill hole a closed container, filled with liquid carbon dioxide under pres sure, connecting the container to a source of supply of li uid carbon dioxide and forcing additional iquid carbon dioxide into the closed container under suflicient ressure to rupture a wall of the container, t e rupture of the container wall permitting the gasification of the carbon dioxide which causes a blasting pressure in the drill hole.

Signed at Harrisburg, Illinois, this thirteenth (13), day of October, 1924.

DENT FERRELL. A. W. HELMHOL'FZ. 

